Sprint Important Notes:- The new software version is: 13.11.3Q2.X-69-3-8- A notification will be sent to the device when the update is available- Updates are released in stages. When checking for the update, you may receive a message that no update is available, check back later or wait until the update notification is sent to your device- Refer to the Moto X Software Update article in Support for install instructions.

Not sure if you already got your answer or not, but sure, you can do this over WiFi and is usually the preferred way to download the update. And as far as the “Check For Updates” button, it does something but not much. What I mean is, Google’s updates rollout to ever larger groups over about two weeks. The phones that get the updates are completely random, and groups are added I think once a day or so. If your device had been added to the next group to receive the update, but had not yet checked for the update on it’s own, the button would show you the update. Though most of the time pressing the button won’t do much unless your device is ready on Google’s end to receive the update.

Android 4.4, KitKat, is the latest release of the Android platform. KitKat includes enhancements such as restyled status and navigation bars, a new full-screen mode, color emoji support, improved closed captioning support, stronger security, smarter power use, and more tools and capabilities for better app development.

Improved Phone Dialer app with the ability to look up contacts directly from the dial pad, see and tap frequent contacts, and search your corporate directory easily

Incorporated a new version of Google Hangouts that supports integrated SMS/MMS messaging. Hangouts can be set as the default SMS app under Settings>Wireless>Default SMS app.